Process of preparing dyestuffs and intermediates from benzanthrone derivatives



Patented Nov. 10, 1931 UNITED STATES PATENT on- 105 ROBERT FRASER THOMSON AND JOHN THOMAS, OF GRANGEMOUTH, SCOTLAND, AS- SIGNOBS TO SCOTTISH DYES, LIMITED, OF GR-ANGEMOUTH, SCOTLAND PROCESS OF PBEPARIN G DYESTUFFS AND TINTERMEDIATES FRbIM'. BENZALNTHEONE DERIVATIVES No Drawing. Application flied April 8, 1927, Serial This invention relates to the manufacture of dyestuffs and intermediates for the-production of dyestuffs.

The invention in brief consists in a process for the production of dibenzanthronyl bodies and hydroxy benzanthrone compounds from chloro substituted and methyl substituted benzanthrones having the positions 2 and Bzl free by treating these bodies in solution 1 in sulphuric acid with manganese dioxide preferably at a temperature not exceeding 60 C. especially at a temperature between about 0 C. and 20 C. V

The invention also consists in improved processes substantially as indicated herein and in products which may be produced thereby or by the equivalents of these processes. V

The following examples illustrate how the invention may be carried into effect, all parts being parts by weight Ewample 1 105 C.) After cooling the solution to 0 C. it is slowly added to the solution of 6-chlorbenzanthrone in 96 per cent. H SO The mixture is kept at 0 C. for 4 hours, with continuous stirring. After this the temperature is allowed to rise to 10 C. for a period of 24 hours. The. solution is then worked up in the usual Way; for example, by pouring into 500 parts water, to which are added 6 parts of sodium bisulphite, and the whole No. 182,172, and in Great Britain Apri1 22, 1926.

then boiled. The dark brown precipitate is filtered 0E and consists of a mixture of hydroxyechlorbenzanthrone and apparently a dichlor-dibenzanthronyl body. a The hydroxy body that hasbeen formed is removed by extraction with caustic soda solution, and l on acidification the required hydroxy-chlorbenzanthrone is precipitated and can be filtered,washed and dried. Thisproductcan be alkylated in the usual way and condensed to. give the corresponding alkhydroxy-chlor- .dibenzanthrones.

loyer 300 C. It gives a characteristic red vlolet solution'in sulphuric acid. If it is fused with potash (preferably alcoholic) a blue melt is obtained from which a dark obtained.

The structuralformula of the dichlordibenzanthronyl compound is probably as followsi blue dyestufi', resembling dibenzanthrone, is

violet product is obtained which does not Vat readily. l

I Example 2 This deals with the employment as a starting product of iso chlor-benzanthrones prepared by condensation of Q-chlor-anthraquinone with glycerine. v H

According to this example 2-ch1or-anthraquinone is submitted to a process of condensation with glycerine and the resulting product treated by the method of Example 1.

We have found that if the chlor-benzanthrone that is obtained by the condensation of Q-chlor-anthraquinone with glycerine be subjected to similar treatment to that described in Example 1, the yields of hydroxy chlor-benzanthrone and dichlor-dibenzanthronyl are poor.

We believe that this may be attributed to the fact that a single body is not obtained by the condensation of Q-chlor-anthraquinone with glycerine in the usual way.

The Q-chlor-benzanthrone which melts at l89190.5 C. does not apparently give dibenzanthronyls by the method of Example 1,

but the two isometric bodies which are obtained simultaneously, namely the chlorbenzanthrone, melting at 130-134; C., and the chlor-benzanthrone, melting at 18-150 (1, will when treated by the method of Example 1, give good yields of dibenzanthronyls,

Example 3 V This deals with the employment of chlorbenzanthrones obtained by condensation of l-chlor-anthraquinone with glycerine.

According to this example, l-chlor-anthraquinone is submitted to a process of condensation with glycerine and the product treated with manganese'dioxide and sulphuric acid inthe cold by method of Example 1.

As a result there is obtained what is apparently a dichlor Bzl-Bzl'-dibenzanthronyl which can be characterized by its coloura- 'tion in sulphuric acid and also by the fact that it gives a dibenzanthrone on fusion with potash.

By the condensation ofl-chlor-anthraquim one with glycerine there are apparently obtained two mono-chlor-benzanthrones one of which melts at about 180.5181.5 C. and the other apparently an alpha-chlor-benzanthrone melts at about 154.160 C. Either of these products or a combination of both may be used according to the present example.

Ecoample 4 This example deals with the employment of'methyl-benzanthrones having the 2 and B21 positions free. i

According to this example, methyl-benzanthrones as indicated are treated by the method of Example 1.

It the product obtained by condensing Q-methyl-anthraquinone with glycerine, that is crude methyl benzanthrone, is treated by the method of Example 1, we have found that the yield of dibenzanthronyl body is poor. Further, pure Q-methyl-benzanthronedoes not appear to give a Bz1-Bz1-dibenzanthronyl when treated by the method of Example 1. Methyl-benzanthrones which are r not substituted in the 2 position such as may be obtained in varying amounts when 2- methyl-anthraquinone is condensed with glycerine, in these circumstances give dibenzanthronyls which are characterized by the usual tests, namely a red violet solution in sulphuric acid and conversion by potash fuslon to dibenzanthrone bodies.

7 General The products of the processes may be treated as described in U. S. specification No. 1,607,491 and the processes described may be modified on the lines of the processes of that specification.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent is g 1. 'In'the process of preparing dibenzanthronyl bodies and hydroxybenzanthrone compounds, the step which comprises subin which X represents H or C1; Y represents H, Cl'or CH and not more than one G1 atom existing in-thenucleus at the same time; and when Y represents CH then X represents H.

4. In the process of preparing dibenzanthronyl bodies and hydroxy benzanthrone compounds, the step which consists in subecting to action otmanganese dioxide benzanthrones ,comprlsing' the type in which X represents H orCl Y represents H, Cl or CH and not more than one Cl atom existing in the nucleus at, the same time; and 7 when Y represents CH then X represents H.

5. In the process of preparing dibenzanthronyl bodies, and hydroxy benzanthrone com' minds, the step which consists in subjectmg to action of manganese dioxide ben: zanthrones comprising the type in which X represents H or Cl; Y represents H, C1 or CH and not more than one C1 atom existing in the nucleus at the same time; and when Y represents CH then X represents H. In testimony whereof we have signed our names to this specification.

ROBERT FRASER THOMSON.

JOHN THOMAS. 

